Dequeue unused styles scripts

[joshdarby]

Changes

This pull request makes the following changes:

• Dequeues these stylesheets if the amplify-feed query param exists:

  'largo-child-styles',
  'wp-block-library',
  'chosen',
  'wp-job-manager-frontend',
  'navis-slick',
  'navis-slides',
  'largo-stylesheet-gutenberg',
  'link-roundups',

• Dequeues these scripts if the amplify-feed query param exists:

  'largo-modernizr',
  'load-more-posts',

Why

For #132

Testing/Questions

Features that this PR affects:

• Amplify theme and embed template

Questions that need to be answered before merging:

• [x] Is this PR targeting the correct branch in this repository?
• [ ] Are there any other scripts to dequeue?
• [ ] Are there any other stylesheets to dequeue?
• [ ] https://github.com/INN/umbrella-inndev/pull/133/commits/6ce22aaf3230dcae263991d47564e34a8bef4d8c wraps the dequeue functions in a conditional that only fires if the amplify-feed query param is set. Do you think that's necessary?

Steps to test this PR:

1. View the embed template
2. Make sure it's functioning as expected

[benlk]

6ce22aa wraps the dequeue functions in a conditional that only fires if the amplify-feed query param is set. Do you think that's necessary?

Yes.

Are there any other scripts to dequeue?

I'd remove largo_header_js from wp_enqueue_scripts, since we aren't displaying the Largo header: https://github.com/INN/largo/blob/512da701664b329f2f92244bbe54880a6e146431/inc/enqueue.php#L177-L192

Also jquery, jquery-migrate, and the emoji styles, if possible.

[joshdarby]

https://github.com/INN/umbrella-inndev/pull/133/commits/e7a634ef56d67155c8c8b32acabec0c414c23a74 removes largo_header_js, jquery, jquery-migrate, and all of the emoji styles and scripts.

[benlk]

We're down to 117.23 KB / 40.89 KB transferred on my local testing, which is gloriously small. 18.08 KB of the transferred is the header image.